Sterilization of Duodenoscopes Found to Terminate ‘Superbug’ Outbreaks Other effective measures include returning the endoscope to the manufacturer for servicing.

October 3, 2019 Specific measures healthcare facilities have adopted to prevent additional infections after linking a duodenoscope to a “superbug” outbreak are discussed in a new study published in August.

The study reviewed the details of 23 such outbreaks reported since 2012 — 17 in the U.S. and six overseas, primarily in Europe. Fourteen of these cases were due to the CRE superbug and almost half as many to a related multidrug-resistant organism, or MDRO. The remaining cases, in general, were caused by a germ suspected, but not confirmed, to be a related MDRO.

At least one of these MDRO cases was caused by Klebsiella pneumoniae carrying the mcr-1 gene. Bacteria containing this gene can be resistant to colistin — a “last resort” antibiotic — and their infections even more insidious, and deadly, than CRE.

Superbugs found on contaminated duodenoscopes are sometimes also called “high concern organisms.” The FDA defines these as “organisms that are more often associated with disease, such as E. coli and Pseudomonas aeruginosa.” The mortality rate of infections caused by these bacteria, which include CRE, can be as high as 50%. Some colistin-resistant bacterial infections may be untreatable, however.

This August study was published in the peer-reviewed journal British Medical Journal Open Gastroenterology.

In response to six of these almost two dozen cases this study reviewed, sterilization of the duodenoscope using ethylene oxide gas was implemented to improve safety, with at least three healthcare facilities reporting this measure terminated the superbug outbreak. None of the facilities that adopted sterilization reported its failure to prevent additional infections.

Additional details about these 23 outbreaks included determining the suspected cause of each case’s superbug infections, as well as identifying several factors that can adversely impact reprocessing and increase the risk of a duodenoscope transmitting CRE and other multidrug-resistant bacteria.

The 2019 study reported in BMJ-OG also provides recommendations to prevent the transmission of a superbug during ERCP. Duodenoscopes are used more than 500,000 times a year in the U.S. to perform endoscopic retrograde cholangiopancreatography — a medical procedure used to examine and treat disorders of the bile and pancreatic ducts.

Other measures, in addition to sterilization, this study identified to prevent additional infections included re-training staff about proper cleaning of the duodenoscope; culturing the duodenoscope prior to reuse to confirm its safety; and returning the duodenoscope to the manufacturer for evaluation, or maintenance and repair (as warranted).

These 23 outbreaks were identified primarily through a review of the medical literature and the FDA’s adverse event device database. Due to certain search limitations, this study did not identify every eligible outbreak that would have met the study’s inclusion criteria.

This study lists several factors that can adversely impact reprocessing and cause the duodenoscope to remain contaminated and potentially expose patients to CRE or a related MDRO during ERCP. These factors include the duodenoscope’s complex physical design and lacking servicing or repair of the device, among others.

The study defined a MDRO “related” to CRE primarily as a carbapenem-resistant (or, colistin-resistant) gram-negative organism that is not a member of the Enterobacteriaceae family of bacteria, such as P. aeruginosa. Like colistin, carbapenems are last-resort antibiotics.

The original investigation published in 2018 describing the infection of Kl. pneumoniae carrying the mcr-1 gene reported that the transmission of this potentially deadly strain, which occurred in a U.S. acute care hospital, “likely occurred via (a) duodenoscope despite no identifiable breaches in reprocessing or infection control practices.”

Seven of the 23 other investigations this study in BMJ-OG studied similarly reported that the infections occurred despite no identifiable breach in the reprocessing procedure — that is, the duodenoscope was reportedly being reprocessed in accordance with manufacturer’s instructions for use and professional guidelines.

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Expert Consulting Services: LFM-Healthcare Solutions, LLC provides medical expertise and guidance for hospitalsmanufacturers and the public, specializing in healthcare-associated infections linked to medical equipment.



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“Need for improvement” remains, FDA says

While the FDA reports that the incidence has dropped significantly since 2015, cases linking duodenoscope to possible transmission of CRE or a related MDRO continue to be reported, including a case in Texas reported to the FDA earlier this year involving a model with an open elevator-wire channel, which requires reprocessing. (In most current duodenoscope models, this channel is sealed and not reprocessed.)

A duodenoscope.
(Source: FDA)

While their causes are not always evident, such cases highlight the importance of continued vigilance, enhanced measures, and the publication of updated guidance focusing on reducing the risk of both sealed and open duodenoscope models transmitting superbugs.

Earlier this year in April, the FDA issued a notice that said, in part, “there continues to be a need for improvement of the safety of reprocessed duodenoscopes.”

In that same April notice, the FDA provided a new update of the interim results of certain post-market surveillance studies the agency had ordered the three U.S. duodenoscope manufacturers in 2015 to begin performing, reporting that up to 5.4% of “all properly collected samples” obtained from reprocessed duodenoscopes in the clinical setting “tested positive” for high concern organisms.

According to the FDA, these studies were designed with the expectation that the total contamination rate for any one type of organism recovered from a reprocessed duodenoscope would be less than 1%, or near zero.

Transition to sterilization of duodenoscopes?

Just weeks ago in August, the FDA emphasized the importance of reducing this infection risk, recommending in a safety alert that “healthcare facilities and manufacturers begin transitioning to duodenoscopes with disposable components to reduce risk of patient infection.”

The FDA advised in this alert that “because of challenges with cleaning these devices for reuse (reprocessing) and persistent high levels of contamination, the agency is recommending moving away from using duodenoscopes with fixed endcaps to those with disposable components that include disposable endcaps—or to fully disposable duodenoscopes when they become available.”

The FDA added in this alert that “disposable designs simplify or eliminate the need for reprocessing, which may reduce between-patient duodenoscope contamination as compared to reusable, or fixed endcaps.”

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Thinking about shifting to sterilization? Guidance to assist healthcare facilities deciding to replace disinfection with sterilization of flexible endoscopes is provided in two recently published articles entitled, “What You Need to Know When Replacing Disinfection with Sterilization of Flexible Endoscopes” and “Which Flexible Scopes Really Need Sterilization?



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Bronchoscopes also linked to superbug outbreaks

Another article to be published soon in a different journal provides a similar analysis as the August article in BMJ-OG, but of the potential for reprocessed bronchoscopes to transmit concerning organisms.

The article reviews 12 cases in the U.S. and overseas linking use of a bronchoscope to the possible transmission of potentially concerning bacteria, including CRE or a related MDRO. It concludes that this risk is under-recognized and may be significantly higher than reported.

Additionally, the article provides updated guidance and recommendations to enhance reprocessing and improve the safety of flexible bronchoscopes.

Factors the article identifies that can adversely affect reprocessing and pose an increased infection risk include use of a damaged or inadequately serviced bronchoscope, and formation of an inaccessible biofilm inside a bronchoscope.



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Combining this article with the one published in BMJ-OG in August, a total of 35 outbreaks linking the use of either a bronchoscope or a duodenoscope to possible transmission of a superbug were reviewed.

Almost four years ago, the FDA issued a notice entitled, “Infections Associated with Reprocessed Flexible Bronchoscopes: FDA Safety Communication.”

The purpose of this notice, according to the FDA, was “to share preliminary information regarding infections associated with the use of reprocessed flexible bronchoscopes. Although this information is limited, health care providers may benefit from awareness of the issues we are seeing and of steps they can take to mitigate possible risks to patients.”

While this notice acknowledged that “a small number” of reports, at that time, had indicated persistent contamination of the bronchoscope despite the facility reportedly adhering to the manufacturer’s reprocessing instructions, it did not specifically clarify whether bronchoscopes, like duodenoscopes, had been linked to outbreaks of CRE and related MDROs resistant to carbapenems or colistin.

This “in press” article addresses this question.

Also in 2015, the FDA suggested healthcare facilities consider performing at least one of four supplemental measures, which include EO gas sterilization, to improve the effectiveness of duodenoscope reprocessing.

Whether the FDA and Centers for Disease Control and Prevention (CDC) might recommend applying these same four supplemental measures to improve the safety of bronchoscopes (and other types of flexible endoscopes), at least in some circumstances as warranted — for example, in an outbreak setting, or if the bronchoscope is found to be persistently contaminated with bacteria — is unclear.



Article by: Lawrence F Muscarella, PhD. Posted October 3, 2019. Copyright (2019). LFM Healthcare Solutions, LLC. All rights reserved. Dr. Muscarella is the president of LFM Healthcare Solutions, LLC, an independent quality improvement company. Click here for more details about his quality improvement healthcare services


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